A fluidised bed particle engineering approach for simultaneous encapsulation and granulation of an API-based ionic liquid

Solidification of room temperature ionic liquids provides advantages in terms of handling and utilisation in the context of solid dosage forms. Encapsulating drug-based ionic liquids by direct spray operations represents a promising platform for solidifying and formulating these challenging materials. Previous studies have focused on solidification of room temperature active pharmaceutical ingredient (API) ionic liquids (API-ILs) by spray drying. This approach typically results in the production of fine powders that tend to require further processing before they can be incorporated into final solid dosage forms. Fluidised bed granulation is an alternative technology that combines a direct spray operation with a particle size enlargement process. Successfully encapsulating an API-IL using this approach would circumvent suboptimal bulk powder properties of spray dried materials associated with their fine particle size and poor flowability, with the possibility of coating the granular cores with controlled release polymers and blending with additional excipients to yield a highly engineered drug product suitable for direct compression. In the current work a model API-IL was successfully granulated by adapting the spray encapsulation process to operate in a fluidised bed granulator and incorporating an inert filler material in the granulated product. The spray granulated API-IL products from this process were characterised with regard to their particle size, composition, and powder flow properties, and preliminary tabletting studies were performed using the granulates. This is the first demonstrated example of a composite drug product of its kind. • An API-based ionic liquid was granulated for the first in a fluidised bed process. • More than 85 % of the API-IL in the feed was encapsulated in the granulated products. • Granulated products had improved flowability compared to spray dried materials. • Granules were tabletted via direct compression to produce viable drug products. • First example of a drug product containing an encapsulated API-based ionic liquid.